Passage
But now ye rejoice in your boastings: all such rejoicing is evil.
But now ye rejoice in your boastings: all such rejoicing is evil.
James 4:14 Whereas ye know not what shall be on the morrow. For what is your life? It is even a vapour, that appeareth for a little time, and then vanisheth away.
James 4:15 For that ye ought to say, If the Lord will, we shall live, and do this, or that.
James 4:16 But now ye rejoice in your boastings: all such rejoicing is evil.
James 4:17 Therefore to him that knoweth to do good, and doeth it not, to him it is sin.
The verse centers on "rejoice", "boastings", "such", "rejoicing", and "evil". It is saying that the verse draws attention to "rejoice" and "boastings", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 15's "For that ye ought to say If..." into verse 17's "Therefore to him that knoweth to do...", so "rejoice" and "boastings" belong inside that flow. In James context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "rejoice" and "boastings" with trust shaped by these words, not by a vague optimism outside the passage.